Cost Effectiveness Analysis: Malaria Vector Control In Kenya

THE BUDGET FOCUS A Publication of the IEA Budget Information Programme Issue No. 28 November 2011 Cost Effectiveness Analysis: Malaria Vector Control In Kenya Malaria in Kenya is a major epidemic and is ranked second after HIV/AIDs in the burden of disease prevalence. The Kenyan government has both preventive and curative measures for dealing with Malaria pandemic in the country. Under preventive measures the reduction of mosquito vectoral capacity is done using Insecticide Treated Nets (ITNs) and Indoor Residual Spraying (IRS) interventions. These interventions depend on the Malaria epidemiological zones in Kenya. This bulletin is an excerpt from the research work carried out under the Global Development Network (GDN) project on Cost Effectiveness Analysis of Selected Health Sector Programmes in Kenya. The objective of the study was to establish the cost effectiveness of Malaria vector control in Kenya, particularly the IRS and the ITN interventions. The study found that, there was increased use of ITNs following the Abuja Declaration by the African Heads of States in Abuja, Nigeria in April 2000. Using data collected from direct costs associated with ITN and IRS, and using all adult Malaria morbidity as the effectiveness measure, it was found that IRS was more cost effective than ITN. 1. Background Cost effectiveness is an important economic tool for evaluating health interventions. The need for evaluation stems from the fact that populations need to maximize good health, given limited resource availability, and in cases where resources are available, efficiency is paramount. Furthermore, in order to make well informed decisions on which interventions to adopt, there is need for an economic evaluation. Cost effectiveness analysis, therefore, provides policy makers with information on which health interventions to adopt for optimal results, and in other cases, it can also give pointers on how to improve the use of existing interventions that previously did not have much impact. Furthermore, the burden of disease has serious socioeconomic impact in developing countries, which Kenya is not an exception. In the fight against disease, it is important to determine which In this issue 1. Background 2. Malaria Epidemic 3. Strategic Approach to Malaria Management in Kenya 4. Methodology 5. Discussion and Conclusion Pg.1 Pg.2 Pg.4 Pg.4 Pg.6 The Budget Focus 1

strategic approaches are more effective than others. This would assist the country in channelling the scarce and limited resources to health interventions with a much greater impact. The main objective of the Kenyan Government s vision for health is to provide equitable and affordable health care at the highest affordable standard for her citizens (GOK, 2007). The key focus areas of the Government in the health sector are, first, to ensure that there is access to health care by reducing the cost and distance barriers on access to health services. Secondly, there should be equity in access to health care so that all groups, whether strong or vulnerable, are provided with health services. Third, the quality of the services should be of the highest possible standards, and provided efficiently. Fourth, the Government intends to enhance the capacity of the health care system in order for the citizenry to be served well. Last but not least, there is a strong focus on the institutional framework within which health policies operate so that there is a strong integration of stakeholders in the health policy formulation process. These focus areas can only be achieved through ensuring efficient use of the limited competing resources available to finance health care. Among the main objectives is the promotion of preventive health care for all Kenyans. The focus on preventive Malaria vector is important since different strategies have been adopted to fight Malaria which is a major cause of morbidity in Kenya. The study examines the two vector control programmes currently being adopted i.e., the use of bed nets and indoor residual spraying in order to determine which one is cost effective; the focus is on Kenyan fiscal year 2005/06. 2.0 Malaria Epidemic The WHO (2008) cited the HIV/AIDS epidemic, Malaria and tuberculosis as being the diseases that shorten life expectancy. WHO (ibid) notes that the cycle of poverty and ill health is evident in sub-saharan Africa, where approximately 76 per cent of the population live on less than US$ 2 a day and a further 46.5 per cent live on less than US$ 1 a day. Between 1981 and 2001, the GDP of sub-saharan countries decreased by 13 per cent, resulting in the number of those living on less than US$ 1 a day doubling from 164 million to 314 million. The percentage of Africans in the world s poor has also increased from 16 per cent in 1985 to 31 per cent in 1998. At the same time, while progress was made in human development, this has been reversed by HIV/AIDS and armed conflicts. WHO further notes that, in 2002, 72 per cent of deaths were caused by communicable diseases such as HIV/AIDS, tuberculosis, Malaria, respiratory infections, among others. These deaths are largely preventable and account for approximately 23 per cent of mortality in the region. Table 3.1 shows the burden of disease by cause and mortality stratum in Africa. Table 1: The Burden of Disease in sub-saharan Africa Rank Disease High child, high adult ( 000) High child, very high adult( 000) AIDS 14620 49343 Malaria 20070 20785 Respiratory Infection 18976 16619 Perinatal Conditions 10869 10485 Diarrhoea 11548 11689 TOTAL 76083 108921 Source: Africa Region World Health Report (2006) In Kenya, Malaria is a disease of public health significance since its presence has adverse effects of human suffering and its impact on the workforce. Table 1 equally shows that, Malaria ranks second after HIV/AIDS in the burden of disease statistics. Furthermore, the Ministry of Health estimates that, in Kenya, 25 million out of a population of 34 million Kenyans are at risk of Malaria. Moreover, 170 million working days are lost to the disease each year, with Malaria being estimated to cause 20 per cent of all deaths in children under five. Figure 1 provides the Malaria trends for the period 2 The Budget Focus

Figure 1: Malaria Trends in Kenya, 2005-2006 1400000 1200000 Number of Patients 1000000 800000 600000 400000 2006 2005 200000 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Months Source: GOK (2009) 2005-2006. Malaria infection is normally at its peak season in the month of August. Kenya has not been left out in the fight against Malaria. Kenya s efforts can be seen in her commitment to the Abuja Declaration. African Heads of State, meeting in Abuja, Nigeria, in April 2000, issued a declaration committing to achieve significant country targets for Malaria control. At the time Kenya made this commitment, Malaria accounted for up to 30 per cent of outpatient attendance in Kenya and 19 per cent of all admissions to health facilities (GOK, 2009). Kenya then went ahead to develop a national Malaria strategy covering the period 2001-2010, whose main goal is to reduce the level of Malaria infection and consequent death by 30 per cent by the year 2006 and to sustain that improved level of control to 2010. Furthermore, the Government developed Kenya Vision 2030, whose goal for the health sector is to provide equitable and affordable quality health services to all Kenyans. Vision 2030 also aims at restructuring the health care delivery system to shift the emphasis from curative to promotive and preventive health care. It is clear that the Government is committed to fighting Malaria and achieving the Abuja Declaration target. The fight against Malaria requires a good understanding of the Malaria zones in Kenya, which areas are more vulnerable than others. GOK (2009) has grouped the Malaria zones depending on altitude, rainfall patterns and temperature as follows: 1. Endemic: Areas of stable Malaria have altitudes ranging from 0 to 1,300 meters above sea level, and are areas around Lake Victoria in western Kenya and in the coastal regions. Rainfall, temperature and humidity are the determinants of the perennial transmission of Malaria. The vector life cycle is usually short and survival rates are high because of the suitable climatic conditions. 2. Seasonal transmission: Arid and semi-arid areas of northern and south-eastern parts of the country experience short periods of intense Malaria transmission during the rainfall seasons. Temperatures are usually high and water pools created during the rainy season provide breeding sites for the Malaria vectors. The Budget Focus 3

Extreme climatic conditions like the El Niño southern oscillation lead to flooding in these areas, resulting in epidemic outbreaks with high morbidity rates owing to the low immune status of the population. 3. Epidemic prone areas of western highlands of Kenya: Malaria transmission in the western highlands of Kenya is seasonal, with considerable year-to-year variation. Epidemics are experienced when climatic conditions favour sustainability of minimum temperatures around 18oC. This increase in minimum temperatures during the long rains favours and sustains vector breeding, resulting in increased intensity of Malaria transmission. The whole population is vulnerable and case fatality rates during an epidemic can be up to ten times greater than those experienced in regions where Malaria occurs regularly. 4. Low risk Malaria areas: This zone covers the central highlands of Kenya, including Nairobi. The temperatures are usually too low to allow completion of the sporogonic cycle of the Malaria parasite in the vector. Table 2: Population at Risk of Malaria in Kenya Epidemiological Zones Population Projection for 2009 Pregnant Women Children < 1year Endemic 11212645 504569 448506 Seasonal/Arid 8375922 376916 335037 High Epidemic Prone 8007718 360347 320309 Low Risk 11826978 532214 473079 TOTAL 39423263 1774047 1576931 Source: National Malaria Indicator Survey (2009) 3. Strategic Approach to Malaria Management in Kenya The National Malaria Strategy and National Health Sector Strategic Plan 2005-2010 have outlined the strategies for preventing and controlling Malaria. These strategies are in line with the epidemiology of Malaria. The core intervention programmes are: 1. Vector control: using Insecticide Treated Nets (ITNs) and Indoor Residual Spraying (IRS); 2. Case management: using Artemisinin-based Combination Therapies (ACTs) and improved laboratory diagnosis; 3. Management of Malaria in pregnancy; 4. Epidemic preparedness and response; and 5. Cross-cutting strategies: include Information, Education, and Communication (IEC) for behaviour change, as well as effective monitoring and evaluation. Malaria control can be undertaken using both preventive and curative interventions as summarized in Table 3. Treatment or curative interventions focus on Malaria treatment, which can range from outpatient, impatient and home treatment. Prevention of Malaria consists of inhibition of mosquito breeding, reduction of mosquito vectoral capacity, isolation of humans from mosquito and reduction in Malaria morbidity. This study has chosen to examine two preventive measures that reduce mosquito s vectoral capacity; these measures are internal residual spraying and use of insecticide treated bed nets. Table 3: Malaria Control Interventions Principle Goal Treatment Prevention Inhibit mosquito breeding Intervention Outpatient anti-malarial treatment for uncomplicated Malaria following active or passive case detection Inpatient treatment for severe and complicated Malaria Home treatment Source reduction, e.g., drainage, filling in ditches Chemical larviciding Management of agricultural, industrial and urban development to avoid the creation of breeding sites 4 The Budget Focus

Reduction of mosquito vectoral capacity Isolate humans from biting by vector mosquitoes Reduce Malaria infection and morbidity in humans Indoor residual spraying Insecticide-treated materials, e.g., bed nets, curtains in some circumstances Insecticide-treated materials, e.g., bed nets, curtains Repellents and domestic insecticides, e.g., sprays, coils, burning traditional herbs Chemoprophylaxis for non-immune groups, e.g., children, pregnant women, migrants Intermittent treatment of pregnant women (2008) further acknowledges that the effect of ITN becomes more apparent when ITN coverage increases. ITNs are used by individuals within the households, and in 2006, approximately 7 million ITNs were distributed to individuals within the households in Kenya. Indoor Residual Spraying (IRS) is the most commonly used form of Malaria vector control given that its application has been standardized the world over with clear specifications on equipment and insecticides and technical and operational guidelines (WHO, ibid). Table 4: Type of Vector Control Quantity and Cost (2006) 4. Methodology 4.1 Malaria Cost Data There are various methods that have been put forward in collecting data for cost effectiveness analysis. McIntosh and Luengo-Fernandez (2006) provide costs that can be used for economic evaluation; these costs are divided into direct costs associated with health care resource, related services and cost to patients and their families/friends. Indirect costs, on the other hand, are related to time lost from work and costs external to health and welfare services. This analysis has used direct costs data associated with Malaria vector control. The cost of ITN and IRS were derived from the World Malaria Report. This cost data was assumed to include all costs associated with implementing the vector control programme; this included personnel, facilities, material and equipment, and any other input. ITN tends to add a chemical barrier to the already imperfect physical barrier hence improving the effectiveness in personal protection (WHO, 2006). The main objective of the use of ITN is to reduce the contacts between human beings and mosquitoes for individual, family and community protection. Evidence from Binka et al. (1998) show that, there is an overall 17 per cent reduction in child mortality of age 6-59 months associated with the use of ITN. WHO Type of Vector Control Quantity Total Expenditure (USD) Insecticide treated bed nets (ITN) distributed to households No. of households protected by Indoor Residual Spraying (IRS) Source: World Malaria Report (2008) 7102752 17500000 110000 3800000 IRS kills mosquitoes entering the houses and also resting on sprayed surfaces. IRS, unlike ITN, protects communities and therefore must have a wider coverage; it further requires that a population accepts the spraying of its households once or twice a year. Comparing ITN and IRS, ITN requires continuous use of bed nets, while IRS requires a community s acceptance of spraying; however, the attitude towards spraying could change with time. 4.2 Measure of Effectiveness The effectiveness measure for Malaria vector control has varied depending on the studies undertaken. Binka et al. (1998), used reduction in all-cause mortality in young children as a measure of effectiveness. Even while using child death averted as the measure of effectiveness, they highlighted the main weakness of this measure in that, there could be other environmental factors, influencing Malaria mortality, such as proximity to health facilities and potential breeding sites of mosquitoes. However, because of the difficulty in The Budget Focus 5

measuring Malaria specific mortality in rural areas of Africa, where causes of death are assigned by verbal autopsy, this was the only available measure. The Cochrane Review (1998) concluded that ITNs reduce overall mortality by about 20 per cent in Africa and that, for every 1,000 children aged 1-59 months protected by ITNs, about six lives are saved each year. Therefore, child deaths averted can be a good effectiveness measure of Malaria control. Table 5: Protective efficacy of ITN and IRS (95% CI) Outcome ITN IRS Overall 0.63 (0.58-0.68)* 0.75 (0.73-0.76)* Less than 5 years 0.66 (0.51 0.84) 2 0.72 (0.65-0.81)*** 5-15 years 0.37 (0.02-1.00) 2 0.68 (0.63-0.73)** Greater than 15 years 0.70 (0.62-0.80)*** 0.82 (0.81-0.84)* Age adjusted 0.59 (0.29 0.77)** 0.75 (0.58 0.85)* 2 not significant at 5% level, *P <0.001, **P <0.01, ***P <0.05 Guyatt et al. (2002), in their study of Malaria prevention in the Kenyan highlands in Nyamache Division Gucha district, found that, overall, sleeping under insecticide treated net reduced the risk of Malaria infection by 63 per cent, while sleeping in a room sprayed with insecticide reduced the risk of Malaria infection by 75 per cent, as compared to households that neither had bed nets nor sprayed their houses. Table 5 show the protective efficacy of use of ITNs and IRS by age cohorts as compared to a control group that neither used any. 5. Discussion and Conclusion From the calculations of cost effectiveness, as shown on Table 6, the indoor residual spraying is more cost effective since it has a lower cost effectiveness ratio than that of insecticide treated bed nets. In attempting to understand the dynamics of Malaria control in Kenya, it would be important to acknowledge that, while both IRS and ITN are vector control mechanisms, the IRS has largely been used in Kenya for epidemic preparedness response in western highlands to prevent Malaria (GOK, 2007). Table 6: Cost Effectiveness Ratio Type of Vector Control No. of households protected by Indoor Residual Spraying (IRS) Insecticide Treated Bed nets (ITNs) distributed to households Total Expenditure (US$) Overall Malaria Morbidity CE Ratio 3800000 0.75 5066666.67 17500000 0.63 27777777.78 Source: Author s estimates from WHO (2008) and World Malaria Report (2008) The ITN has been distributed country-wide to prevent Malaria, particularly in children and pregnant women, in line with the targets set at the Abuja summit by African Heads of State in April 2000, where there was to be a scale up in the use of ITNs by protecting 80 per cent of children under five and pregnant women against Malaria in Africa by the year 2010 (GOK, 2009). This can explain why there has been increased usage of ITNs as compared to IRS. Furthermore, according to the Kenya Malaria Strategy Report, the monitoring and evaluation of IRS has been weak. These findings show that, the national Malaria control programme in Kenya should re-examine the strategies being adopted to prevent Malaria under vector control, with the objective of ensuring efficiency in all vector control initiatives undertaken. 6 The Budget Focus

References Binka F. N., F. Indome and T. Smith. (1998) Impact of Spatial Distribution of Permethrin- Impregnated Bed Nets on Child Mortality in Rural Northern Ghana American Journal of Tropical Medical Hygiene, 59(1): 80-85. Government of Kenya. (2007). Implementation of IRS Campaign in Malaria Epidemic Prone Districts in Kenya 2007. Division of Malaria Control, Ministry of Public Health and Sanitation. Government of Kenya (2009). 2007 Malaria Indicator Survey. Division of Malaria Control, Ministry of Public Health and Sanitation. Guyatt et al. (2002). Malaria Prevention in Highland Kenya: Indoor Residual Spraying vs. Insecticide Treated Bed nets. Tropical Medicine and International Health, l.7 (4): 298-303). Lengeler C. Insecticide-treated bed nets and curtains for Malaria control (Cochrane Review). The Cochrane Library 1998; (3).Oxford. McIntosh E. and Luengo-Fernandez Ramon. (2006). Economic evaluation. Part 1: Introduction to the concepts of economic evaluation in health care. Journal of Family Planning and Reproductive Health Care, 32(2): 107-112. WHO (2008). Global Burden of Disease Report.http://www.who.int/healthinfo/ global_burden_disease/gbd_report_2004update_annexa.pdf The Budget Focus 7

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